Encyclopedia of

Nortriptyline

Definition

Nortriptyline is a tricyclic antidepressant. It is sold in the United
States under the brand names Aventyl and Pamelor, and is also available
under its generic name.

Purpose

Nortriptyline is used to relieve symptoms of depression. The drug is more
effective for endogenous depression than for other forms of depression.
Endogenous depression is depression arising from metabolic changes within
a person, such as chemical or hormonal imbalances. Nortriptyline is also
used occasionally to treat
premenstrual depression,
attention-deficit/hyperactivity disorder
in children, and bed-wetting (
enuresis
).

Description

Tricyclic antidepressants act to change the balance of naturally occurring
chemicals in the
brain
that regulate the transmission of nerve impulses between cells. The
precise way in which nortriptyline elevates mood is not fully understood.
The drug inhibits the activity of
neurotransmitters
such as acetylcholine, histamine, and 5-hydroxytryptamine. Studies have
indicated that nortriptyline interferes with the release, transport, and
storage of catecholamines, another group of chemicals involved in nerve
impulse transmission.

Recommended dosage

As with any antidepressant, the dose of nortriptyline must be carefully
adjusted by the physician to produce the desired therapeutic effect.
Nortriptyline is available in 10-, 25-, 50-, and 75-mg capsules as well as
in a 10 mg/5mL solution. The usual dosage for nortriptyline is 25 mg given
three or four times each day. The optimum total dose of the drug is 50 to
150 mg daily. Total dosage in excess of 150 mg is not recommended. The
recommended dose for older adults (over age 60) and adolescents is 30 to
50 mg per day. Nortriptyline is not recommended for use by children.

The therapeutic effects of nortriptyline, like other tricyclic
antidepressants, appear slowly. Maximum benefit is often not evident for
two to three weeks after starting the drug. People taking nortriptyline
should be aware of this and continue taking the drug as directed even if
they do not see immediate improvement.

Once symptoms of depression have been controlled, the lowest dosage that
maintains the effect should be taken. People who take 100 mg or more of
nortriptyline per day should have their blood tested periodically for
nortriptyline concentrations. The results of these tests will show whether
the dose is appropriate, too high, or too low.

Precautions

Like all tricyclic antidepressants, nortriptyline should be used
cautiously and with close physician supervision in people, especially the
elderly, who have benign prostatic hypertrophy, urinary retention, and
glaucoma, especially angle-closure glaucoma (the most severe form). Before
starting treatment, people with these conditions should discuss the
relative risks and benefits of treatment with their doctors to help
determine if nortriptyline is the right antidepressant for them.

A common problem with tricyclic antidepressants such as nortriptyline, is
sedation (drowsiness, lack of physical and mental alertness). This side
effect is especially noticeable early in therapy. In most patients,
sedation decreases or disappears entirely with time, but until then,
patients taking nortriptyline should not perform hazardous activities
requiring mental alertness or coordination. The sedative effect is
increased when nortriptyline is taken with other central nervous system
depressants, such as alcoholic beverages, sleeping medications, other
sedatives, or antihistamines. It may be dangerous to take nortriptyline in
combination with these substances.

Nortriptyline may increase the possibility of having
seizures
. Patients should tell their physician if they have a history of seizures,
including seizures brought on by the abuse of drugs or alcohol. These
people should use nortriptyline only with caution and be closely monitored
by their physician. Nortriptyline can also cause ringing in
the ears, tingling in the extremities, and numbness in the extremities,
although none of these side effects are common when the drug is used as
directed.

When used by people with
schizophrenia
, nortriptyline may worsen psychotic, increase hostility in some patients,
or activate other symptoms that had not previously been expressed. When
used by people with
bipolar disorder
(manic-depressive illness), symptoms of mania may be magnified. Patients
with a history of
suicide
attempts, thoughts of suicide, or drug overdose should be monitored
carefully when using nortriptyline. Nortriptyline can either increase or
decrease blood sugar levels, depending on the patient and his or her
medical condition. Nortriptyline should be used with great caution when a
patient is receiving
electroconvulsive therapy
.

Nortriptyline may increase heart rate and cause irregular heartbeat. It
may also raise or lower blood pressure. It may be dangerous for people
with cardiovascular disease, especially those who have recently had a
heart attack, to take this drug or other antidepressants in the same
pharmacological class. In rare cases in which patients with cardiovascular
disease must receive nortriptyline, they should be monitored closely for
cardiac rhythm disturbances and signs of cardiac stress or damage.

Side effects

Nortriptyline shares side effects common to all tricyclic antidepressants.
The most frequent of these are dry mouth, constipation, urinary retention,
increased heart rate, sedation, irritability, dizziness, and decreased
coordination. As with most side effects associated with tricyclic
antidepressants, the intensity is highest at the beginning of therapy and
tends to decrease with continued use.

Dry mouth, if severe to the point of causing difficulty speaking or
swallowing, may be managed by dosage reduction or temporary
discontinuation of the drug. Patients may also chew sugarless gum or suck
on sugarless candy in order to increase the flow of saliva. Some
artificial saliva products may give temporary relief.

Men with prostate enlargement who take nortriptyline may be especially
likely to have problems with urinary retention. Symptoms include having
difficulty starting a urine flow and more difficulty than usual passing
urine. In most cases, urinary retention is managed with dose reduction or
by switching to another type of antidepressant.

Problems associated with the skin (loss of sensation, numbness and
tingling, rashes, spots, itching and puffiness), seizures and ringing in
the ears have also been reported. Nausea, vomiting, loss of appetite,
diarrhea and abdominal cramping are associated with nortriptyline usage.
Skin rash, sensitivity to sunlight and itching have been linked to
nortriptyline use. People who think they may be experiencing any side
effects from this or any other medication should talk to their physicians.

Interactions

Dangerously high blood pressure has resulted from the combination of
tricyclic antidepressants, such as nortriptyline, and members of another
class of antidepressants known as monoamine oxidase (MAO) inhibitors.
Because of this, nortriptyline should never be taken in combination with
MAO inhibitors. Patient taking any MAO inhibitors, for example Nardil (
phenelzine
sulfate) or Parmate (
tranylcypromine
sulfate), should stop the MAO inhibitor then wait at least 14 days before
starting nortriptyline or any other tricyclic antidepressant. The same
holds true when discontinuing nortriptyline and starting an MAO inhibitor.

Cimetidine (Tagamet) may slow the elimination of nortriptyline, thus
effectively increasing the dosage of nortriptyline. Quinidine also raises
the circulating levels of the drug, requiring a decrease in the dosage of
nortriptyline.

The sedative effects of nortriptyline are increased by other central
nervous system depressants such as alcohol, sedatives, sleeping
medications, or medications used for other mental disorders such as
schizophrenia. The symptoms of increased heart rate, blurred vision, and
difficulty urinating are additive with other drugs such as
benztropine
,
biperiden
,
trihexyphenidyl
, and antihistamines.